How to detect whether a "text/writeable" field is focused - autohotkey

Question

How do I detect whether a text/writable field is focussed?
By text/writable field, I mean e.g. notepad; this SO-text field; the address-bar of Chrome, etc. Basically anything that you are supposed to write into.

Answer 1

Sounds like you want ControlGetFocus, it lets you get which control of a target window that has input focus. What kind of window will really make a difference, IE is pretty doable, Notepad++ also doable, Chrome would require special code for example: https://autohotkey.com/board/topic/103178-how-to-get-the-current-url-in-google-chrome/#entry637687.
Example of getting the control of the active window that works pretty well:
!z::
activeWindow := WinExist("A")
ControlGetFocus, focusedControl, ahk_id %activeWindow%
if(ErrorLevel) {
MsgBox, Couldn't get focusedControl
} else {
ControlGetText, focusText, %focusedControl%
if(ErrorLevel) {
ControlGetText, focusText,, ahk_id %activeWindow%
Msgbox, Focused window text: %focusText%
} else {
Msgbox, Focused control text: %focusText%
}
}
return
So you would want to find out the identifier of what ever field you were interested in and check if it has focus when you want to know, or maybe regularly with SetTimer.